Flex die punching apparatus and method

ABSTRACT

Disclosed is a flex die punching apparatus for forming an aperture in at least one sheet of material. There is a flexible, extrudable platen which, upon exertion of a force against it, extrudes at least a portion of at least one sheet of material through an aperture of a die. The flexible, extrudable platen may have a punch feature, corresponding to the shape and position of the die aperture, which assists in the extruding of the flexible, extrudable platen through the die aperture and also in the formation of the aperture in the sheet of material. In another embodiment of the invention, there may be a second die wherein the at least one sheet of material is placed between the first and second dies to form the aperture in the sheet of material.

The application is a continuation of application Ser. No. 08/457,634,filed Jun. 1, 1995, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus and method for machiningfeatures in sheets of material, and more particularly, relates to anapparatus and method which are simple in use and flexible in operation.

In the current manufacture of multilayer ceramic (MLC) substrates forintegrated circuit semiconductor package structures, a plurality ofceramic sheets is formed by doctor blading a slurry containing a resinbinder, a particulate ceramic material, solvents, and a plasticizer,drying the doctor bladed sheet, and blanking it into appropriate sizedgreensheets. Via holes are then mechanically punched for formingelectrical interconnections through the sheet. Holes may also be punchedin the greensheets to form cavities which will eventually hold theintegrated circuit semiconductor device. Electrically conductive pasteis deposited in the holes, and in appropriate patterns on the surface ofthe greensheets, the greensheets stacked and laminated, and the assemblysubsequently fired at an appropriate sintering temperature.

There are several methods of forming the cavities in the greensheets.One of these is custom machined punch and die sets. While this method isadvantageous for manufacturing large numbers of parts, the machinedpunch and die sets are expensive and require long lead times. Inaddition, this method is inflexible for manufacturing new cavity designsor moderate numbers of parts.

Another method for forming cavities is an energy beam system such as theelectron beam system disclosed in Booke et al. U.S. Pat. No. 5,124,522,the disclosure of which is incorporated by reference herein. Here anelectron beam is utilized to machine features in a greensheet. Thesekinds of systems can easily handle design changes but they involve largecapital expenses and long process times. Also of interest is thescanning laser drilling system disclosed in LaPlante et al. U.S. Pat.No. 5,168,454, the disclosure of which is incorporated by referenceherein. Again, the laser drilling system has great flexibility but isexpensive and throughput of the system is a concern.

It would be desirable to have a system that is more flexible, simplerand less expensive to form cavities.

Kumagai Japanese Published Patent Application JP02-139202, thedisclosure of which is incorporated by reference herein, discloses asystem for punching holes in a greensheet which consists of a bottomplate, die, silicone rubber platen and ram. When a greensheet is placedbetween the die and platen, and force is applied by the ram, the platenforces portions of the greensheet into the apertures of the die. Theplaten itself is eventually extruded into the apertures of the die,thereby displacing the portions of the greensheet and forming holes orapertures in the greensheet. While this system is effective, it is notwithout its problems. For example, rounding of the greensheets at theholes occurs, i.e., sharp holes are not formed. This rounding is madeeven worse when thicker greensheets are utilized.

Deshet U.S. Pat. No. 4,856,399, the disclosure of which is incorporatedby reference herein, discloses an apparatus very similar to Kumagaiabove. Deshet, in addition, discloses that the surface of the platenfacing the die is heterogeneous in nature, containing localized regionsof higher hardness than surrounding areas of the platen. The localizedregions of higher hardness aid in the forming of holes with sharpercorners in thin sheets. The thin sheets may be metallic or nonmetallic.It is apparent that the sharpness of the holes would depend on thelocation of the localized regions of higher hardness. In addition,Deshet would still have problems with thicker sheets of material.

Thus, there still remains a need for a punching apparatus and methodwhich are simple in use and flexible in operation that could producesharp apertures in sheets of material.

Accordingly, it is a purpose of the present invention to have a punchingapparatus and method which are simple in use and flexible in operationfor making apertures in sheets of material.

It is another purpose of the invention to have a punching apparatus andmethod for making sharp-cornered apertures in sheets of material.

It is yet another purpose of the invention to have a punching apparatusand method for making sharp-cornered apertures in thin and thick sheetsof materials.

These and other purposes of the invention will become more apparentafter referring to the following description of the invention consideredin conjunction with the accompanying drawings.

BRIEF SUMMARY OF THE INVENTION

The purposes of the invention have been achieved by providing, accordingto a first aspect of the invention, a flex die punching apparatuscomprising:

a first plate;

a die having at least one aperture positioned adjacent to the firstplate;

a flexible, extrudable platen positioned adjacent to the at least oneaperture of the die and adjacent to at least a portion of the remainderof the die, the flexible, extrudable platen having at least one punchfeature corresponding to the shape and position of the at least oneaperture of the die; and

a second plate positioned adjacent to the flexible, extrudable platen;

wherein, in operation, when at least one sheet workpiece is interposedbetween the flexible, extrudable platen and the die and then the firstand second plates are forced together, the at least one punch feature ofthe flexible, extrudable platen is caused to extrude a portion of the atleast one sheet workpiece through the at least one aperture of the die,thereby forming at least one sheet workpiece having at least oneaperture corresponding to the shape and position of the at least oneaperture of the die.

According to a second aspect of the invention there is provided a flexdie punching apparatus comprising:

a first plate;

a first die having at least one aperture positioned adjacent to thefirst plate;

a second die having at least one aperture positioned adjacent to thefirst die, the at least one aperture in the first and second dies beingin alignment;

a flexible, extrudable platen positioned adjacent to the at least oneaperture of the second die and adjacent to at least a portion of theremainder of the second die; and

a second plate positioned adjacent to the flexible, extrudable platen;

wherein, in operation, when at least one sheet workpiece is interposedbetween the first and second dies and then the first and second platesare forced together, the flexible, extrudable platen is caused toextrude a portion of the at least sheet workpiece through the at leastone aperture of the first die, thereby forming at least sheet workpiecehaving at least one aperture corresponding to the shape and position ofthe at least one aperture of the first die.

According to a third aspect of the invention, there is provided a methodof forming at least one aperture in at least one sheet of materialutilizing a flex die punching apparatus, the apparatus having a firstplate, a die having at least one aperture positioned adjacent to thefirst plate, a flexible, extrudable platen positioned adjacent to the atleast one aperture of the die and adjacent to at least a portion of theremainder of the die, the flexible, extrudable platen having at leastone punch feature corresponding to the shape and position of the atleast one aperture of the die, and a second plate positioned adjacent tothe flexible, extrudable platen, the method comprising the steps of:

placing at least one sheet of material between the flexible, extrudableplaten and the die; and

forcing the first and second plates together, the at least one punchfeature of the flexible, extrudable platen being caused by the step offorcing to extrude a portion of the at least one sheet of materialthrough the at least one aperture of the die, thereby forming the atleast one sheet of material having at least one aperture correspondingto the shape of the at least one aperture of the die.

According to a final aspect of the invention, there is provided a methodof forming at least one aperture in at least one sheet of materialutilizing a flex die punching apparatus, the apparatus having a firstplate, a first die having at least one aperture positioned adjacent tothe first plate, a second die having at least one aperture positionedadjacent to the first die, the at least one aperture in the first andsecond dies being in alignment, a flexible, extrudable platen positionedadjacent to the at least one aperture of the second die and adjacent toat least a portion of the remainder of the second die, and a secondplate positioned adjacent to the flexible, extrudable platen, the methodcomprising the steps of:

placing a first sheet of material between the first and second dies;

forcing the first and second plates together, the extrudable platenbeing caused by the step of forcing to extrude a portion of the firstsheet of material through the at least one aperture of the first die,thereby forming the first sheet of material having at least one aperturecorresponding to the shape of the at least one aperture of the firstdie.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematical cross-sections of the apparatusaccording to the present invention showing a punch feature andstiffening material in the platen.

FIGS. 2A and 2B are schematical cross-sections of the apparatusaccording to the present invention showing a thin, hard layer ofmaterial on the platen.

FIG. 3A is a plan view of the punch feature of FIG. 1 while FIG. 3B is aperspective view showing the punch feature as it would protrude from theplaten during the punching operation.

FIGS. 4A and 4B are schematical cross-sections of the apparatusaccording to the present invention showing a second die and furthershowing stiffening material in the platen.

FIGS. 5A and 5B are schematical cross-sections of the apparatusaccording to the present invention showing a second die and furthershowing a punch feature and stiffening material in the platen.

FIGS. 6A and 6B are schematical cross-sections of the apparatusaccording to the present invention showing a second die and furthershowing a punch feature on the platen and stiffening material in theplaten.

FIGS. 7A and 7B are schematical cross-sections of the apparatusaccording to the present invention showing a second die and furthershowing a thin, hard layer of material on the platen.

FIGS. 8A and 8B are schematical cross-sections of the apparatusaccording to the present invention showing a second die and furthershowing transfer punching of one sheet material into a second sheetmaterial.

FIG. 9 is a schematical cross-section of the apparatus according to thepresent invention similar to FIG. 1A but modified to show the flexible,extrudable platen only extending partially across the surface of thedie.

FIG. 10 is a schematical cross-section of the apparatus according to thepresent invention similar to FIG. 4A but modified to show the flexible,extrudable platen only extending partially across the surface of thedie.

FIG. 11 is an exploded perspective view of the apparatus of FIG. 1according to the present invention.

FIGS. 12A and 12B are schematical cross-sections of the apparatusaccording to the present invention showing a third die and furthershowing transfer punching of one sheet of material into a second sheetof material.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the Figures in more detail, where like numbers havebeen used to refer to like features, and particularly referring to FIGS.1A and 1B, there is disclosed according to the invention a flex diepunching apparatus 10. The flex die punching apparatus 10 comprises afirst plate 12, a die 14 positioned adjacent to the first plate 12, aflexible, extrudable platen 16, and a second plate 18 positionedadjacent to the flexible, extrudable platen. The die 14 has at least onehole or perforation or aperture (hereafter just aperture) 20.

As shown in the Figures, the die has two apertures but it should beunderstood that there may more or less than two apertures, depending onthe use to which the invention is put.

While the flexible, extrudable platen 16 is shown extending across thewhole surface of the die 14, the flexible, extrudable platen 16 may, infact, only cover part of the die surface. FIG. 9 shows the flex dieapparatus 10 of FIG. 1 except that the flexible, extrudable platen 16does not extend across the whole surface of the die 14. Voids or areas17 represent space which is not occupied by platen 16. That is, theflexible, extrudable platen 16 is positioned so that it is adjacent tothe aperture 20 of the die 14 and also adjacent to at least a portion ofthe remainder of the surface 22 of the die 14. The advantages to thisparticular embodiment of the flexible, extrudable platen 16 will becomemore apparent hereafter.

An important element of the flexible, extrudable platen 16 is punchfeature 24 corresponding to the shape and position of the aperture 20 ofthe die 14. In general, punch feature 24 should be about the same sizeand shape of aperture 20 since punch feature 24 will be extruded throughaperture 20 during operation of the flex die punching apparatus 10.Punch feature 24 in flexible, extrudable platen 16 is distinct from theremainder of the surface of the flexible, extrudable platen as shown inFIG. 1A. The punch feature 24 will be further discussed in more detailhereafter.

The relationship of the different parts of the invention can be seenmore clearly by reference to FIG. 11 wherein the flex die punchingapparatus 10 is shown by an exploded view.

Referring back to FIGS. 1A and 1B, in operation, at least one sheetworkpiece 26 would be placed between die 14 and flexible, extrudableplaten 16. Thereafter, first plate 12 would be forced against secondplate 18 as indicated by arrows 29 to begin compressing the flexible,extrudable platen 16. This may be accomplished by making one of thefirst and second plates 12, 18 stationary and moving the other of thefirst and second plates 12, 18 towards the one. Alternatively, both thefirst and second plates 12, 18 may be made movable, in which case theywould move towards each other. Whether the first plate 12 or the secondplate 18 is stationary or neither of them is stationary is unimportantto the invention.

During operation of the flex die punching apparatus 10, the flexible,extrudable platen 16, particularly punch feature 24, is allowed toextrude through aperture 20 of the die 14. As a consequence, flexible,extrudable platen 16 causes portion 28 of the sheet workpiece 26 to beremoved from the remainder of the sheet workpiece 26, thereby forming asheet workpiece 26 having an aperture 30. Aperture 30 will have a shapeand position corresponding to the shape and position of aperture 20 ofdie 14. Die 14 should be at least as thick as, and preferably thickerthan, sheet workpiece 26 so as to accommodate portion 28 withoutinterfering with the formation of aperture 30 of sheet workpiece 26. Therelative thickness of die 14 will generally be true of all of theembodiments of the present invention except the embodiment of FIGS. 8Aand 8B.

Punch feature 24 is shown in more detail in FIGS. 3A and 3B. In the planview of FIG. 1A, defined feature 24 is shown as being circular in shapewhich would correspond to a circular shape of aperture 20 in die 14. Itis assumed that an aperture with a circular shape is desired. With theteachings of the present invention, any shape may be used for punchfeature 24 and aperture 20. As best seen in FIG. 1A, there is a gap 32between punch feature 24 and flexible, extrudable platen 16. Gap 32 ispresent as a result of the way punch feature 24 is formed. For example,a circular shape may be laser drilled in the flexible, extrudable platen16 by laser drilling around the periphery of the desired shape. If laserdrilling is used, the method and apparatus disclosed in the aboveLaPlante U.S. Pat. No. 5,168,454 is preferred. During laser drilling, itis important to only partially perforate the flexible, extrudable platen16 so that gap 32 is formed, resulting in the formation of punch feature24. In operation, punch feature 24 protrudes from flexible, extrudableplaten 16, as shown in FIGS. 1B and 3B. Since punch feature 24 is closein shape, dimension and position to desired aperture 30 in sheetworkpiece 26, aperture 30 will have sharp, clean edges.

As discussed earlier, flexible, extrudable platen 16 may only partiallycover die 14, as shown in FIG. 9. The advantage to this embodiment ofthe invention is that less force is needed to extrude flexible,extrudable platen 16 through aperture 20 of die 14.

Referring again to FIGS. 1A and 1B, another element of the invention isillustrated. Flexible, extrudable platen 16 may also comprise astiffening material 34 inserted into the punch feature 24. Thestiffening material 34 is stiffer than the flexible, extrudable platen16. Due to the stiffening material 34, the forces generated due to themoving together of the first plate 12 and the second plate 18 can bemore easily translated to punch feature 24, thereby more easilyaccomplishing the forming of aperture 30 in sheet workpiece 26.

Now referring to FIGS. 2A and 2B, there is disclosed another embodimentaccording to the present invention. Flex die punching apparatus 10' ofFIGS. 2A and 2B is identical to flex die punching apparatus of FIGS. 1Aand 1B except that now flexible, extrudable platen 16 includes a thin,hard layer of material 36 uniformly deposited on the surface of theflexible, extrudable platen 16 that faces the die 14. The thin, hardlayer of material 36 is bonded to that part of the flexible, extrudableplaten 16 that is adjacent to the die 14 and is also bonded to the punchfeature 24. The thin, hard layer of material 36 may be selected from thefollowing group of materials: ceramics (e.g., boron nitride, alumina,aluminum nitride, titanium nitride, etc.), metals and composites (e.g.,hard particles in a binder such as diamond in epoxy). It is believedthat the thin, hard layer of material 36 will assist in achieving theformation of apertures 30 with sharp corners in the sheet workpiece.

A further embodiment of the invention is illustrated in FIGS. 4A and 4B.The flex die punching apparatus 50 comprises a first plate 52, a firstdie 54 positioned adjacent to the first plate 52, a second die 56positioned adjacent to the first die 54, a flexible, extrudable platen58 positioned adjacent to the second die 56 and a second plate 60positioned adjacent to the flexible, extrudable platen 58. Each of firstdie 54 and second die 56 has at least one aperture 62, 64, respectively.Aperture 62 of first die 54 should be in alignment with aperture 64 ofsecond die 56.

As noted earlier, flexible, extrudable platen 58 need not extend acrossthe entire surface of second die 56. However, it must extend across (orbe adjacent to) aperture 64 and at least a portion of the second die 56,as shown in FIG. 10. As before, reducing the cross-sectional area of theflexible, extrudable platen 58 reduces the amount of force necessary toextrude the flexible, extrudable platen 58 into the apertures 62, 64 offirst and second dies 54, 56, respectively.

In operation, at least one sheet workpiece 68 would be placed betweenfirst die 54 and second die 56. Thereafter, first plate 52 would beforced against second plate 60 as indicated by arrows 66 to begincompressing the flexible, extrudable platen 60. This may be accomplishedby making one of the first and second plates 52, 60 stationary andmoving the other of the first and second plates 52, 60 towards the one.Alternatively, both the first and second plates 52, 60 may be mademovable, in which case they would move towards each other.

During operation of the flex die punching apparatus 50, as more clearlyillustrated in FIG. 4B, the flexible, extrudable platen 58 is allowed toextrude through aperture 64 of second die 56 and then aperture 62 offirst die 54. As a consequence, flexible, extrudable platen 58 causesportion 70 of the sheet workpiece 68 to be removed from the remainder ofthe sheet workpiece 68 and transported through aperture 62 of first die54, thereby forming a sheet workpiece 68 having an aperture 72. Theresulting sheet workpiece 68 has at least one aperture 72 thatcorresponds to the shape and position of the aperture 62 of the firstdie 54.

The addition of second die 56 provides several important advantages tothe invention. One is that thicker sheets may be punched. Another isthat the apertures formed are clean and sharp, thereby forming asuperior aperture. A further advantage is that multiple sheets may bemore easily punched.

In another embodiment of the invention, as also illustrated in FIGS. 4A,4B, 5A and 5B, the flexible, extrudable platen 58 may also comprise astiffening material 74 inserted into the flexible, extrudable platen 58.Where there is a punch feature, such as punch feature 76 of flex diepunching apparatus 50' of FIGS. 5A and 5B, the stiffening materialshould be located within the punch feature. On the other hand, wherethere is no punch feature, the stiffening material 74 should be locateddirectly adjacent to the aperture 64 of the second die 56 as shown inFIGS. 4A and 4B. The stiffening material 74 is stiffer than theflexible, extrudable platen 58. Due to the stiffening material 74, theforces generated due to the moving together of the first plate 52 andthe second plate 60 can be more easily translated through the flexible,extrudable platen 58, thereby more easily accomplishing the forming ofthe aperture 72 in the sheet workpiece 68.

A further embodiment of the invention is illustrated in FIGS. 5A and 5B.The flex die punching apparatus 50' is identical to the flex diepunching apparatus 50 of FIGS. 4A and 4B except that now flexible,extrudable platen 58 includes punch feature 76 therein. Punch feature 76should, in general, correspond to the shape and position of the aperture64 of the second die 56 and aperture 62 of the first die 54. Punchfeature 76 should be about the same size and shape of the apertures 62,64 since punch feature 76 will be extruded through apertures 62, 64during operation of the flex die punching apparatus 50'. As notedpreviously with respect to the embodiment of FIGS. 1A and 1B, punchfeature 76 in flexible, extrudable platen 58 is distinct from theremainder of the surface of the flexible, extrudable platen 58.

FIGS. 6A and 6B illustrate a further embodiment of the presentinvention. The flex die punching apparatus 50" is identical to the flexdie punching apparatus 50 of FIGS. 4A and 4B except that now flexible,extrudable platen 58 includes at least one feature 80 on the flexible,extrudable platen 58. As shown in FIGS. 6A and 6B, the feature 80 may bea metallic material but any hard, wear-resistant material should besufficient for the purposes of the present invention. The feature 80corresponds to the shape and position of the apertures 62, 64 of thefirst and second dies 54, 56, respectively. For example, if apertures62, 64 were circular, feature 80 should be circular as well. As can beappreciated, feature 80 acts as a punch, driven by the flexible,extrudable platen 58, to remove portion 70 of the sheet workpiece 68.Feature 80 also is effective in forming clean, sharp apertures in sheetworkpiece 68. Flexible, extrudable platen 58 in flex die punchingapparatus 50" may also include a stiffening material 74 as discussedpreviously.

FIGS. 7A and 7B illustrate yet another embodiment of the presentinvention. The flex die punching apparatus 50"' is identical to the flexdie punching apparatus 50 of FIGS. 4A and 4B except that now flexible,extrudable platen 58 includes a thin, hard layer of material 86 on thesurface of the flexible, extrudable platen 58 that faces the second die56. As discussed previously with respect to the embodiment of FIGS. 2Aand 2B, the thin, hard layer of material 86 is bonded to that part ofthe flexible, extrudable platen 58 that is adjacent to the second die 56and is also bonded to the flexible, extrudable platen 58 that isadjacent to the apertures 64 of the second die 56. If the flexible,extrudable platen 58 also includes a punch feature 76, the thin, hardlayer will also be bonded to the punch feature 76, as shown in FIGS. 7Aand 7B.

While the sheet workpiece material has been stated to be a greensheetmaterial, it should be understood that this material is only specifiedfor purposes of illustration and not limitation. Other sheet workpiecematerials that may be useful in the present invention are, for example,metals, plastics, and other nonmetallic materials.

The flexible, extrudable platen for use in the present invention may bemade from any suitable elastic or resilient material. Preferredmaterials should be elastomeric, abrasion-resistant and have a thicknessof 1/16 to 1/4 inch, preferably 1/8 inch. Some of the preferredmaterials meeting these requirements are silicone elastomers. The mostpreferred material is 9255 series silicone rubber sold by the CHRDivision of the Furon Co., New Haven, Conn.

The die material is not important to the present invention so long asthe material is somewhat wear-resistant, machinable and sufficientlyrobust to withstand the rigors of punching. Suitable materials includemost thin, flexible sheet metals. Stainless steel sheet metals, forexample, are desirable. Structural ceramics are also useful in thepresent invention. The apertures in the die material may be cut usingany kind of machining method. Particularly preferred is the laserdrilling method disclosed in the above LaPlante U.S. Pat. No. 5,168,454.The die aperture may be any shape desired, for example, circular,square, triangular, to name a few.

The stiffening material may be selected from any number of materialsthat would cause the stiffening material to be stiffer than theflexible, extrudable platen. Some of these stiffening materials may be,for example, metals, epoxies, plastics, ceramics, rubber etc.

As shown in the Figures, the stiffening material does not extend all theway through the flexible, extrudable platen. It is within the scope ofthe present invention for the stiffening material to extend all the waythrough the flexible, extrudable platen. It is also within the scope ofthe present invention for the flexible, extrudable platen to be porous,and preferably for the pores to run continuously through the thicknessof the flexible, extrudable platen so that it takes on the appearance ofswiss cheese. Then, the pores can be selectively filled with a stifferor harder material to enhance the operation of the apparatus accordingto the present invention. It should be understood that the stiffeningmaterial need only be stiffer than the surrounding flexible, extrudableplaten. Thus, the flexible, extrudable platen may be made from arelatively soft rubber while the stiffening material is made from arelatively hard rubber. It is also possible for the flexible, extrudableplaten to be made from a porous material, like foam rubber, and thenhave the pores of the foam rubber selectively filled with epoxy or otherstiff material.

The shape of the punch feature should be the same as the shape of thedie aperture. Thus, the shape of the punch feature may also be any shapedesired, for example, circular, square, triangular, to name a few.

The operation of the present invention may be varied so as tosimultaneously punch at least a second sheet workpiece 88. The flex diepunching apparatus 50 as shown in FIGS. 8A and 8B is identical to theflex die punching apparatus 50 of FIGS. 4A and 4B. However, thedimension of first die 54 has been modified so that its thickness is thesame as that of sheet workpiece 68. The reason for this will becomeapparent hereafter. In operation, sheet workpiece 68 is placed betweenthe first die 54 and the second die 56, as before. Now, however, thereis a second sheet workpiece (i.e., sheet workpiece 88) added to theapparatus which is positioned between second die 56 and flexible,extrudable platen 58. When force 66 is applied, flexible, extrudableplaten 58 will cause at least a portion 90 of sheet workpiece 88 to beextruded into sheet workpiece 68, thereby displacing portion 70 of sheetworkpiece 68. The aperture 72 that would normally be present in sheetworkpiece 68 after punching is filled by portion 90 of sheet workpiece88. In this manner, "transfer punching" of one material into a secondmaterial may be easily accomplished.

Alternatively, sheet workpiece 68 and second sheet workpiece 88 may bothbe placed between the first die 54 and the second die 56. Then, punchingwould take place as above described with respect to FIGS. 8A and 8B.

FIGS. 12A and 12B illustrate a final embodiment of the presentinvention. The embodiment of the flex die punching apparatus 100 isidentical to flex die punching apparatus 50 except that there is now theaddition of third die 94. In operation, flex die punching apparatus 100works similarly to flex die punching apparatus 50 as illustrated inFIGS. 8A and 8B except that now, second sheet workpiece 88 is placedbetween second die 56 and third die 94. Transfer punching isaccomplished in a similar manner with the added benefit that portion 90is more precisely formed. Too, the addition of the third die 94 allowsthicker sheet workpieces to be punched with precision.

Lastly, while all the embodiments of the invention have been shown withthe orientation of the apparatus as shown in the Figures, the apparatuscan also work when rotated to a different orientation, for example, 180degrees from its present orientation.

It will be apparent to those skilled in the art having regard to thisdisclosure that other modifications of this invention beyond thoseembodiments specifically described here may be made without departingfrom the spirit of the invention. Accordingly, such modifications areconsidered within the scope of the invention as limited solely by theappended claims.

What is claimed is:
 1. A flex die punching apparatus comprising:a firstplate; a die having at least one aperture positioned adjacent to thefirst plate, the aperture having a shape, a size and a position withrespect to the die; a flexible, extrudable platen positioned adjacent tothe at least one aperture of the die and adjacent to at least a portionof the remainder of the die, the flexible, extrudable platen having atleast one punch feature corresponding to the shape, size and position ofthe at least one aperture of the die, there being but one punch featurefor each aperature; and a second plate positioned adjacent to theflexible, extrudable platen; wherein, in operation, when at least onesheet workpiece is interposed between the flexible, extrudable platenand the die and then the first and second plates are forced together,the at least one punch feature of the flexible, extrudable platen iscaused to move towards the first plate and through the at least oneaperture of the die so as to extrude a portion of the at least one sheetworkpiece through the at least one aperture of the die, thereby formingat least one aperture in the at least one sheet workpiece correspondingto the shape and position of the at least one aperture of the die. 2.The flex die punching apparatus of claim 1 further comprising a thin,hard layer of material bonded to the flexible, extrudable platen that isadjacent the die and is bonded to the at least one feature.
 3. The flexdie punching apparatus of claim 2 wherein the thin, hard layer ofmaterial is selected from the group consisting of ceramics, metals andcomposites.
 4. The flex die punching apparatus of claim 1 wherein the atleast one punch feature of the flexible, extrudable platen is situatedwithin the flexible, extrudable platen and comprises partial perforationof the flexible, extrudable platen so as to define a periphery of the atleast one punch feature.
 5. The flex die punching apparatus of claim 1wherein the die comprises thin, flexible sheet metal.
 6. The flex diepunching apparatus of claim 1 wherein the flexible, extrudable platencomprises a rubber.
 7. The flex die punching apparatus of claim 1further comprising a stiffening material inserted into the at least onepunch feature of the flexible, extrudable platen, the stiffeningmaterial being stiffer than the flexible, extrudable platen.
 8. The flexdie punching apparatus of claim 7 wherein the stiffening material isselected from the group consisting of metals, epoxies, plastics,ceramics and rubbers.
 9. A flex die punching apparatus comprising:afirst plate; a first die having at least one aperture positionedadjacent to the first plate, the aperture having a shape, a size and aposition with respect to the die; a second die having at least oneaperture positioned adjacent to the first die, the aperture having ashape, a size and a position with respect to the die, the at least oneapertures in the first and second dies being in alignment; a flexible,extrudable platen positioned adjacent to the at least one aperture ofthe second die and adjacent to at least a portion of the remainder ofthe second die, the flexible, extrudable platen having at least onepunch feature corresponding to the shape, size and position of the atleast one apertures of the first and second dies, there being but onepunch feature for each corresponding pair of at least one apertures inthe first and second dies; and a second plate positioned adjacent to theflexible, extrudable platen; wherein, in operation, when at least onesheet workpiece is interposed between the first and second dies and thenthe first and second plates are forced together, the at least one punchfeature of the flexible, extrudable platen is caused to extrude aportion of the at least one sheet workpiece through the at least oneaperture of the first die, thereby forming at least one aperture in theat least one sheet workpiece corresponding to the shape and position ofthe at least one apertures of the first and second dies.
 10. The flexdie punching apparatus of claim 9 further comprising a thin, hard layerof material bonded to the flexible, extrudable platen that faces thesecond die and is bonded to the at least one punch feature.
 11. The flexdie punching apparatus of claim 11 wherein the thin, hard layer ofmaterial is selected from the group consisting of ceramics, metals andcomposites.
 12. The flex die punching apparatus of claim 9 wherein theat least one punch feature of the flexible, extrudable platen comprisespartial perforation of the flexible, extrudable platen around thecircumference of the at least one punch feature.
 13. The flex diepunching apparatus of claim 9 wherein the first and second dies comprisethin, flexible sheet metal.
 14. The flex die punching apparatus of claim9 wherein the flexible, extrudable platen comprises a rubber.
 15. Theflex die punching apparatus of claim 9 further comprising a stiffeningmaterial inserted into the at least one punch feature of the flexible,extrudable platen, the stiffening material being stiffer than theflexible, extrudable platen.
 16. The flex die punching apparatus ofclaim 15 wherein the stiffening material is selected from the groupconsisting of metals, epoxies, plastics, ceramics and rubbers.
 17. Theflex die punching apparatus of claim 9 further comprising a stiffeningmaterial inserted into the flexible, extrudable platen and adjacent tothe at least one punch feature of the flexible, extrudable platen, thestiffening material being stiffer than the flexible, extrudable platen.18. The flex die punching apparatus of claim 17 wherein the stiffeningmaterial is selected from the group consisting of metals, epoxies,plastics, ceramics and rubbers.